Self-supporting ladder



Patented Oct. 14, 1924.

UNITED STATES PATENT OFFICE.

WILLIS PRINCE, OF MONMOUTH, MAINE.

SELF-SUPPORTING LADDER.

Application filed February 18, 1924. Serial No. 693,595.

To all whom it may concern.

Be it known that I, VVILLIS FRINGE, a citizen of the United States, residing at Monmouth, in the county of Kennebec and State of Maine, have invented certain new and useful Improvements in Self-Supporting Ladders; and I do declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention aims to provide a very convenient self-supporting ladder which may be easily folded when not in use, yet will be exceptionally rigid when extended, the device being primarily intended for use by fruitpickers.

Another object of the invention is to make novel provision to cause the ladder. to stand evenly upon the ground regardless of irregularities in the latter.

YVith the foregoing in view, the invention resides in the novel subject matter hereinafter described and claimed, the description being supplemented by the accompanying drawing.

Figure 1 is a perspective view of a ladder constructed in accordance with my invention. 1

Figures 2 and 3 are vertical sectional views as indicated by lines 22 and 33 of Figure 1.

Figure 4 is a detail perspective view showing the ladder bracing structure in a difierent position from that disclosed in Fig. 1.

In the drawing above briefly described, the numerals 1 designate a pair of stiles which carry rungs 2 of any desired form, the upper ends of said stiles being preferably secured against a spacing block 3, while I prefer to provide their lower ends with a pair of spikes 4 adapted to penetrate the ground to prevent slippage.

A pair of arms 5 are located near the upper ends of the stiles 1 and are pivoted at 6 to said stiles, the free ends of said arms having alined bearings 7. These bearings receive trunnions 8 on the upper end of a legged brace structure 9, upon whose upper end, the lower edges of the stiles 1 are intended to rest. The trunnions 8 are provided with pins 10 or other suitable stops, adapted to abut the outer sides of the bearings '7, and the outer sides of the stiles 1 are provided with wedges 11 to engage the inner sides of said bearings, thus wedging the latter tightly outward against the stops 10, when the ladder is set up in condition for use. By this construction, the bracing structure 9 and the main ladder structure may be pivotally adjusted as occasion may require but will be effectively held in any adjusted position. In some instances, it desired, thearms 5 may be swung downwardly as indicated in Fig. 4, instead of upwardly as shown in Figs. 1. and 3, as the ladder may be more conveniently used in this condition, in certain cases.

The brace structure 9 preferably comprises a pair of legs 12 having their upper end portions secured against opposite sides of a spacing block 13, and to form the trunnions 8, I preferably make riseof a horizontally elongated cylindrical member 1 1- whose lower side is notched as at 15 to receive the upper extremities of said legs 12 and block 13, any suitable means, such as a bolt 16 being provided for securing the member 1 1 to the block 13. By employing this construction, the end walls of the notch 15 eifectively hold the legs 12 against the block 13, sothat they cannot separate to any extent from the latter.

I have shown a pair of spacing bars 17 and 18 extend-ing between the legs 12, and upper and lower rods 19 and '20 also extending between said legs, the rod 20 being near the lower ends of the legs and the bar 18 being slightly above this rod. This last named bar is preferably enlarged at its center and formed with an elongated slot 21 which opens through its upper and lower edges. An extension 22 is provided to contact with the inner side of either of the legs 12, said extension being formed with a vertical slot 23 receiving the rod 20. Suitable means, such as T-headed bolts 25, having thumb-nuts 26, may be provided to secure the extension 22 against the inner side of either of the legs 12. To effectively brace the extension 22, regardless of its position, I provide a brace arm 27 which is pivoted at 28 to the upper end of said extension. This brace arm inclines from the pivot 28 and passes through the slot 21, the upper end of said arm being formed with a longitudinal slot 29. A clamping and pivot bolt 30 passes through the cross bar 18 and through the slot 29 and may well be proloosening the nuts 31 and 26 however, it will be seen that vertical adjustment of the extension is permitted. Also, by turning one of the bolts so that its head will slip through the slot 23, the extension may be moved into engagement with the opposite leg 12 whenever desirable.

Excellent results may be obtained from the details disclosed and they may therefore be followed if desired, but within the scope of the invention as claimed,-num'erous minor changes may be made.

I claim:

1. A ladder comprising rung-supporting stiles,a pair of vertically movable arms pivoted to the outer sides of said stiles near theirupper ends, the'free ends of said arms having alined bearings, a legged brace structure upon whose upper end the lower edges of said stiles may rest, said brace structure having oppositely extending trunnions received in the aforesaid bearings and provided with stops to abut the outer sides of said bearings, and wedge surfaces carried by said stiles to wedge said bearings tightly outward against said stops. 7

Y 2. A ladder comprising rung-supporting stiles, a pair of vertically movable arms pivoted to the outer sides of said stiles near their upper ends, the free ends of said arms having alined bearings, a pair of brace legs for said stiles, a block between the upper ends of said legs to which they are secured, a horizontally elongated stile supporting member extending across the upper edge of said block and the upper ends of said legs and having trunnion-forming ends projecting laterally from said legs and received in said bearings, the lower side of said mem- I outer sides of said bearings, and wedge surfaces carried by said stiles and adapted to force said bearings tightly outward against said stops.

3. A ladder comprising spaced legs, a

cross bar connecting said legs above their lower ends, .an extension movable from one of said legs to the other and adapted to contact with the inner side of either, means for securing said extension to either leg for vertical adjustment, a brace arm pivoted to the upper end of said extension and adapted to incline in eitherof two directions therefrom, said arm crossing said cross bar, and means pivotally and adjustably connecting said arm to substantially the center of said cross bar. i i

4. A ladder comprising spaced legs, a

cross bar connecting said legs above their lower ends and having'a. central slot opening through its upper and lower edges, an extension movable from one of said legs to the other and adapted to contact with the inner side of either, said extension having a vertical slot, fastening means adapted for passage through the last named slot to secure the extension adjustably to either of said legs, abrace arm pivoted to the upper end of said extension and passing through the slot of the aforesaid cross bar, said arm having a slot, and a clamping and pivot bolt passing through said cross bar and said slot of the arm.

In testimony whereof I have hereunto affixed my signature. 1

' WILLIS PRINCE.- 

